angular2
Version:
Angular 2 - a web framework for modern web apps
241 lines (240 loc) • 8.24 kB
JavaScript
import { global, isFunction, stringify } from 'angular2/src/facade/lang';
var _nextClassId = 0;
function extractAnnotation(annotation) {
if (isFunction(annotation) && annotation.hasOwnProperty('annotation')) {
// it is a decorator, extract annotation
annotation = annotation.annotation;
}
return annotation;
}
function applyParams(fnOrArray, key) {
if (fnOrArray === Object || fnOrArray === String || fnOrArray === Function ||
fnOrArray === Number || fnOrArray === Array) {
throw new Error(`Can not use native ${stringify(fnOrArray)} as constructor`);
}
if (isFunction(fnOrArray)) {
return fnOrArray;
}
else if (fnOrArray instanceof Array) {
var annotations = fnOrArray;
var fn = fnOrArray[fnOrArray.length - 1];
if (!isFunction(fn)) {
throw new Error(`Last position of Class method array must be Function in key ${key} was '${stringify(fn)}'`);
}
var annoLength = annotations.length - 1;
if (annoLength != fn.length) {
throw new Error(`Number of annotations (${annoLength}) does not match number of arguments (${fn.length}) in the function: ${stringify(fn)}`);
}
var paramsAnnotations = [];
for (var i = 0, ii = annotations.length - 1; i < ii; i++) {
var paramAnnotations = [];
paramsAnnotations.push(paramAnnotations);
var annotation = annotations[i];
if (annotation instanceof Array) {
for (var j = 0; j < annotation.length; j++) {
paramAnnotations.push(extractAnnotation(annotation[j]));
}
}
else if (isFunction(annotation)) {
paramAnnotations.push(extractAnnotation(annotation));
}
else {
paramAnnotations.push(annotation);
}
}
Reflect.defineMetadata('parameters', paramsAnnotations, fn);
return fn;
}
else {
throw new Error(`Only Function or Array is supported in Class definition for key '${key}' is '${stringify(fnOrArray)}'`);
}
}
/**
* Provides a way for expressing ES6 classes with parameter annotations in ES5.
*
* ## Basic Example
*
* ```
* var Greeter = ng.Class({
* constructor: function(name) {
* this.name = name;
* },
*
* greet: function() {
* alert('Hello ' + this.name + '!');
* }
* });
* ```
*
* is equivalent to ES6:
*
* ```
* class Greeter {
* constructor(name) {
* this.name = name;
* }
*
* greet() {
* alert('Hello ' + this.name + '!');
* }
* }
* ```
*
* or equivalent to ES5:
*
* ```
* var Greeter = function (name) {
* this.name = name;
* }
*
* Greeter.prototype.greet = function () {
* alert('Hello ' + this.name + '!');
* }
* ```
*
* ### Example with parameter annotations
*
* ```
* var MyService = ng.Class({
* constructor: [String, [new Query(), QueryList], function(name, queryList) {
* ...
* }]
* });
* ```
*
* is equivalent to ES6:
*
* ```
* class MyService {
* constructor(name: string, @Query() queryList: QueryList) {
* ...
* }
* }
* ```
*
* ### Example with inheritance
*
* ```
* var Shape = ng.Class({
* constructor: (color) {
* this.color = color;
* }
* });
*
* var Square = ng.Class({
* extends: Shape,
* constructor: function(color, size) {
* Shape.call(this, color);
* this.size = size;
* }
* });
* ```
*/
export function Class(clsDef) {
var constructor = applyParams(clsDef.hasOwnProperty('constructor') ? clsDef.constructor : undefined, 'constructor');
var proto = constructor.prototype;
if (clsDef.hasOwnProperty('extends')) {
if (isFunction(clsDef.extends)) {
constructor.prototype = proto =
Object.create(clsDef.extends.prototype);
}
else {
throw new Error(`Class definition 'extends' property must be a constructor function was: ${stringify(clsDef.extends)}`);
}
}
for (var key in clsDef) {
if (key != 'extends' && key != 'prototype' && clsDef.hasOwnProperty(key)) {
proto[key] = applyParams(clsDef[key], key);
}
}
if (this && this.annotations instanceof Array) {
Reflect.defineMetadata('annotations', this.annotations, constructor);
}
if (!constructor['name']) {
constructor['overriddenName'] = `class${_nextClassId++}`;
}
return constructor;
}
var Reflect = global.Reflect;
// Throw statement at top-level is disallowed by closure compiler in ES6 input.
// Wrap in an IIFE as a work-around.
(function checkReflect() {
if (!(Reflect && Reflect.getMetadata)) {
throw 'reflect-metadata shim is required when using class decorators';
}
})();
export function makeDecorator(annotationCls, chainFn = null) {
function DecoratorFactory(objOrType) {
var annotationInstance = new annotationCls(objOrType);
if (this instanceof annotationCls) {
return annotationInstance;
}
else {
var chainAnnotation = isFunction(this) && this.annotations instanceof Array ? this.annotations : [];
chainAnnotation.push(annotationInstance);
var TypeDecorator = function TypeDecorator(cls) {
var annotations = Reflect.getOwnMetadata('annotations', cls);
annotations = annotations || [];
annotations.push(annotationInstance);
Reflect.defineMetadata('annotations', annotations, cls);
return cls;
};
TypeDecorator.annotations = chainAnnotation;
TypeDecorator.Class = Class;
if (chainFn)
chainFn(TypeDecorator);
return TypeDecorator;
}
}
DecoratorFactory.prototype = Object.create(annotationCls.prototype);
return DecoratorFactory;
}
export function makeParamDecorator(annotationCls) {
function ParamDecoratorFactory(...args) {
var annotationInstance = Object.create(annotationCls.prototype);
annotationCls.apply(annotationInstance, args);
if (this instanceof annotationCls) {
return annotationInstance;
}
else {
ParamDecorator.annotation = annotationInstance;
return ParamDecorator;
}
function ParamDecorator(cls, unusedKey, index) {
var parameters = Reflect.getMetadata('parameters', cls);
parameters = parameters || [];
// there might be gaps if some in between parameters do not have annotations.
// we pad with nulls.
while (parameters.length <= index) {
parameters.push(null);
}
parameters[index] = parameters[index] || [];
var annotationsForParam = parameters[index];
annotationsForParam.push(annotationInstance);
Reflect.defineMetadata('parameters', parameters, cls);
return cls;
}
}
ParamDecoratorFactory.prototype = Object.create(annotationCls.prototype);
return ParamDecoratorFactory;
}
export function makePropDecorator(decoratorCls) {
function PropDecoratorFactory(...args) {
var decoratorInstance = Object.create(decoratorCls.prototype);
decoratorCls.apply(decoratorInstance, args);
if (this instanceof decoratorCls) {
return decoratorInstance;
}
else {
return function PropDecorator(target, name) {
var meta = Reflect.getOwnMetadata('propMetadata', target.constructor);
meta = meta || {};
meta[name] = meta[name] || [];
meta[name].unshift(decoratorInstance);
Reflect.defineMetadata('propMetadata', meta, target.constructor);
};
}
}
PropDecoratorFactory.prototype = Object.create(decoratorCls.prototype);
return PropDecoratorFactory;
}